Vulcanization accelerator



UNITED STATES PATENT OFFICE.

MORRIS L. WEISS, OF BROOKLYN, NEW YO RK, ASSIGNOR TO DOVAN CHEMICAL CORPO- VULCANIZATION ACCELERATOR.

No Drawing.

To all 41: ham it may concern Be it known that I. Momus L. WEISS, a citizen of the United States, residing the borough of Brookl n, county of Kings,city and State of New ork, have invented certain new and useful Improvements in Vulcanization Accelerators, of which the following is a full, clear, concise, and exact descriptlon.

The object of my invention is to improve rubber compounds sothat the finished product shall be of superior quality and so that the time required for vulcanization shall be greatly reduced over that ordinarily required for such purpose. It is known that when certain organic substances are added to the rubber mix during the compounding, a catalytic or similar action is produced which causes the rubber or similar gum to unite or react more rapidly and thoroughly with sulphur or other vulcanizing agents.

I have discovered that disubstituted guanidines particularly diphenylguanidine is particularly effective for this purpose. This substance is indicated by the formula I am aware that disubstituted guanidines have been produced by laboratory methods and have been known to chemists for many years beginning about the year 1848 with the work of A. W. Hoffman (An. Chem. Parm. 67-129), but down to time of my researches in accelerators of this type, it was apparently not known that di-substituted g'uanidines were eflicacious or useful as accelerators 1n vulcamzlng, nor that this substance could be produced in sufliciently large quantities in a substantially pure form, or at a sufliciently low cost to be available for this purpose.

I am aware that triphenylguanidine has been suggested, and probably used to some extent. as an accelerator in the vulcanization of rubber, but the use of diphenylguanidine for that purpose appears to have my researches on this substance.

I have found that diphen lguanidine is much more powerful and e cacious as an accelerator in vulcanization than triphenylguanidine. For example, in theivulcaniza- Specification of Letters Patent.

. of new rubber,

Patented Mar. 28, 1922.

Application filed November 12, 1921. Serial No. 514,727.

tion of hard rubber articles the use of diphenylguanidine not only hastens the vulcanizatlng action but results in a final product much superior in texture, strength,durability and aging ualities over that when the triphenylguani ine is used. A greatly improved product also results when .d1 phenylguanidine is used as an accelerator in .the vulcanization of soft rubber compounds,

particularly as regards elasticity, aging qualities and freedom from bloom. In these and similar instances, it has been found that the use of triphenylguanidine re-' quires from two to three times as long a period in vulcanizing as when diphenylguanidine-is used, particularly at lower heat or steam pressures than those commonly employed.

In my prior application Serial No. 482,143 filed July 2,1921, I have described and claimed a process for producing and purifying diphenylguanidine in commercial quantities, and have therein given a rsum of the historical development of the methods of producing the same.

As set forth in said application, I, at present, refer to produce my improved accelerator by desulphurizing thiocarbanilide by the action of a metallic oxide, such as lead oxide, zinc oxide, etc., in an alcoholic solution of an ammonium salt, such as ammonium nitrate.

The present patent application therefore relates to the vulcanization of rubber or similar substances, in which disubstituted guanidines are em loyed as the acceleratmg agent or cata yzer, and particularly di henyl'guanidine.

he method of carrying out my invention, which I at present deem preferable, may be illustrated by the following example:

The rubber may be compounded in the following proportions: parts by weight 45.5 parts by weight of weight. of sulphur,

zinc oxide, 3.5 parts by henylguanidine.

1 art by weight of di These, are mixed toget er in any suitable way, such as by milling, and then vulcanized or cured in the usual molds or otherwise under heat corresponding to a steam ressure of about 40 lbs. per square inch. ihis vulcanizing temperature should be continued until the compound is suitably vulcanized, which requires from 10 to 20 durabilit of the final product is greatly improve and the tendency commonly present in vulcanized rubber to bloom and become brittle with age is greatly reduced if not entirely obviated. My im roved accelerator is particularly useful an valuable where it is desired to produce a harder or less elastic portion in an article leaving other parts which are required to be more elastic and flexible, such as in automobile tires where the headstock is usually made harder than the body or carcass of the tire roper. The relative amounts of vulcanizing agent and accelerator may be so proportioned that the various parts of a single article may be cured to different degrees of hardness without danger of over-curing the softer or more elastic parts. I have found moreover that dip does not need zinc oxide to shorten the time of cure. I however prefer to use zinc oxide on account of its effects on the physical properties of the roduct.

Having thus descrlbed this example of my invention and the method of using the same, I do not wish to be understood as being limited to the exact proportions, ingredients, temperatures, etc., indicated, for various changes may be made without deartin from the essential features of my invention as set forth in the accompanying claims.

What I claim and desire to Letters Patent is:

protect by 1. The process of treating rubber or similar materials, which comprises combining with the rubber compound a di-substituted guanidine.

2. The rocess of treating rubber or similar materials which comprises combining enylguanidine with rubber compound a di-substituted guanidine comprising two phenyl radicles or with the rubber compound diphenylguam idine.

5. The process of treating rubber or similar materials which comprises combining with the rubber compound a vulcanizing agent and a di-substituted guanidine accelerator.

6. The process of treating rubber or similar materials which comprises combining with the rubber compound a vulcanizing agent and a di-substituted guanidine comprisingltwo phenyl radicles or groups.

7 T e process of treating rubber or similar materials which comprises combining with the rubber compound a vulcanizing agent and an accelerator derived from thiocarbanilide in which the sulphur is substituted by an imide group.

8. The process of treating rubber or similar materials, which comprises combining with the rubber compound a vulcanizing agent and diphenylguanidine.

9. A vulcanizing compound of rubber or similar material combined with a vulcanizing agent and a di-substituted guanidine.

10. A vulcanized compound of rubber or similar material combined with a vulcanizing agent and (ii-substituted guanidine comprising two phenyl radicles or groups.

11. A vulcanized compound of rubber or similar material combined with a vulcanizin agent and an accelerator derived from thiocarbanilide in which the sulphur is substituted by an imide group.

12. A vulcanized compound of rubber or similar material combined with a vulcanizing" agent and diphen lguanidine.

igned at New Yor N. Y.,' November MORRIS L. WEISS.

DISCLAIM-5BR.

1,4i1 1.Hon1'a L. Weiss, Brooklyn, N. Y. Vmmunon Aocnmhvn. Patant ated March 28, 1922. Disclaimer filed August 9, 1927, by the gssignea, Down Ohema'cal Corporation, pabntee assuming. Hereby disclaims from tha scope of any of the claims oi said Ixttors Patent all (ii-substituted guanidines excopt the one shown in the illustrative formula of. said pnltgnt, and except di-substi iltad-guanidines wherein one or mom of the hydrogen Moms of either or both of the phenyl (C,H,) groups in said illustrative formula may be substih1t e l by a hydrocarbon radical.

[Oficial Gazette Auguat 30, 1927.] 

